The present invention relates to a device for transmitting current between two end points between which there extends a ribbon cable arranged in a housing and having at least two electric conductors, the ribbon cable which serves for the electrical connection being coiled and its length being substantially greater than the distance between the two end points, at least one of the two end points being moveable relative to the other and conductors of a further extending line being adapted to be electrically connected to the conductors of the ribbon cable (German OS 36 41 706).
Apparatus having such devices are used, for instance, for the feeding of currents for impact protection in an automotive vehicle, in which case an electric conductor is arranged in the steering wheel thereof. One essential problem in connection with these instruments is the transmission of current between fixed and moveable parts. This problem occurs in all devices in which there are two end points which are moveable relative to each other and one of which is developed, in most cases, as a fixed point. The wiper contacts or wiper rings which have been known for a long time for such cases are subject to wear and are disadvantageous particularly in the case of low current intensities, in view of the varying contact resistances.
In the aforementioned device known from German OS 36 41 706, the transmission of current is effected by the ribbon cable which is mounted in the manner of a spring housing. Upon a relative rotary movement of the two end points which are connected by the ribbon cable, the coiled ribbon cable changes in diameter, or "breathes", like the spring of a clock. The windings are contracted to a small diameter in the one direction of rotation. In the other direction of rotation they return to a larger diameter. Conductors of a further extending line are connected to the insulated conductors of the ribbon cable. In this way, a complete device consisting of coiled ribbon cable and connected further extending lines is created. This device can be used only for a specific case of use to which the length and shape of the further extending lines are adapted. The connection of other lines to the ribbon cable requires other tools.